Testing system.



E. R. LUNDIUS.

TESTING SYSTEM.

APPLICATION FILED Ame. 191s.

1,293,825 I, Patented Feb. 11, 1919.

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QM, @F NEW YORK, l. Y., A. COMORATN OF 'EW YGRE TESTING SYS'E.

Specification of Letters latent.

application med April e, 19m. serial; No. 227,088.

To all lwhom t may concern.

Be it known that l, ERIC R. LUNprUs, a citizen of the United States, residing at Brooklyn, in the county of Kings, State of New York, have invented certain new and useful Improvements in Testing Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone systems and more particularly to testing means for such systems.

Heretofore, in providing testing means for separately testing the portion of the telephone line from the subscribers station to the main frame, and the portion extending from the main frame to the switchboard, it has been customary t'o provide switching devices for interrupting the continuity of the telephone line at the main frame or test panel and circuits for looping the telephone f line through a test desk. When the test dii desk is located at a point distant from the central office at which the telephone line terminates, the resistance of the loop between the central oce and the test desk becomes such as to cause considerable transmission loss whenever the telephone line is connected up for testing purposes. Furthermore, the cost of the looping conductors between the central office and the test desk is considerable. It is, therefore, the object of the present invention to provide testing means in connection with test desks located at a point distant from the central oiiice at which terminates the line to be tested, so that practically no transmission loss results from connecting a telephone line up for testing urposes and in which the number of con uctors required between the central oce and the test desk is reduced to a minimum.

In accordance with the features of this invention, there is provided a test line or trunk extending from the test desk to the central oilice where it is double-ended to form a looping circuit when connected with a telephone line which is to be tested. This test line or trunk comprises three conductors, two of which are employed for testing purposes and a third for controlling switching apparatus at the central oiiice by means of which a testing operator may atl will test either section of the telephone line.

This invention will be more fully understood from the following description considered in connection lwith the accompanying drawing illustrating one embodiment thereof.

As shown in the drawing, a telephone line A incoming from a subscribers station to a central .oce switchboard and there terminating in the usual answering jack before reaching the switchboard, passes through switches in the form of jacks 3 and 4, preferablydocated at either a test 'panel or a main distributing frame. A test line B, terminatmg at the central oi'lice in a pair of plugs 5 and 6 for connection with the telephone line A, extends to a test desk located in another odice where it terminates in two Jacks 7 and 8. When the test line B is connected with the telephone line A, the telephone line is then looped through contacts of switching apparatus in the test line located at the central oilice and controlled from the test desk. A cord circuit C provided at the test desk may coperate with either jack of the test line B. When connected with one jack, the switching .apparatus functions to interrupt the continuity of the connected telephone line and to extend one section thereof to the test desk, while if connected with the other jack the continuity of the telephone line is interrupted and the other section thereof is extended to the test desk. rlhe apparatus shown to the right of the dotted line 2 2 is located at the test desk, while that shown to the left thereof is located at the central oce.

The testing operator desiring to test the telephone line A communicates over a separate circuit (not shown) with an attendant at the central oiiice and requests that the test line B be connected with the telephone line A. When the plugs 5 and 6 of the test line B are inserted into the 'jacks 3 and 4 of the telephone line A, the continuity of the line is broken at the normally closed contacts of the jacks, but is immediately restablished through the normally closed contacts of two relays 9 and 10, associated with the central ofce end of the test line B. If,while the test line B is connected with the telephone line A, the subscriber thereof should initiate a call in the usual manner, the removal of the receiver from the switchhook causes the operation of the line relay 11 over a circuit from battery throu h the right-hand winding of relay 11, rightand contact.l of cutoi relay 12, tip contacts of the jack 4 and plug 6, right-hand normal contacts of relays 10 and 9, tip con- -`2o This is usually accomplished by lirst actuat t tacts ofthe plug'5 and the jack 3, out over the other side of the line, through the station apparatus and back over the other side of the line, sleeve contacts of the jack 3 and the plug 5, left-hand normal contacts ofthe ref ays 9 and 10, sleeve contacts of the plug 6 and the jack 4, left-hand contact of cutoff ing key 14 and inserting plug 15 of the cordA circuit C into one of the Jacks, for example, jack 7, and then actuating the listening key 16. The purpose of plugging in when the key 14 is actuated is to prevent the interruption of the telephone line should it happen that a conversation is vbeing carried on atA that time. Finding'that no-conversation is being carried on over the telephone line A, the testing operator lmay restore the key 14 to normal position, whereupon the relay 20, 'operating over a circuit from battery through the contact of the key 14, resistance 21, sleeve contacts of the plug 15 and the jack 7, resistance 22, windlngs of relays 10 and 20, to ground.v Relay 10 is marginal and does not operate. when resistance 22 is included in circuit therewith. Relay 20, in operating causes the operation of relay 9, which opens its contacts, interrupting the continuity of the telephone line A., and disconnectin from the trunk circuit B that' portion of t e telephone line which extends from the jack-3 to the subscribers station,

A and leaving connected with the test desk, 'that portion of the telephone line from th jack 4 to the switch-board.

If the testing operator desires to test the portionof the telephone line A extending from the jack 3 to the subscribers station,

the plug 15 is inserted into the jack 8, and key 14 is restored to normal position. Relays 10 and 20 are thereupon operated. Relay 20, in o erating, causes the operation of relay 9 as above described. Relay 10, in operating, servesto keep the continuity of the telephone line A and to leave connected to the test desk, through the trunk circuit B, that portion of the telephone line extending from the jack 3 to the subscribers line.

If the testing operator upon making 'conneetion -with eitherof the jacks 7 and 8 should find that the-telephone line- A is not in use, the testing of either portion thereof may be carried-on withoutyinterfering with the use of the line by thesubscriben This may be accomplished by 'the momentary act- 4:uation of key 22', whereupon vrelay 23 is energized over a circuit' from battery, through the winding of relay 23 and contact of key 22 to ound". `Immediately upon being energize relay 23 establishes a locking circuit for itself through its middle contact and the contact of relay 20 to ound. -Relay 23, in closing its right and 'le t-hand contacts, connects condensers24 and 25 in multiple with the normally closed contacts of relays 9 and 10. The key 14 is restored to normal position simultaneousl with the operation of the ke 22', vso that t e relay 20 is operated simu taneously with the operation of relay 23. The energization of elther relay'9 or 10l vinterrupts the continuity of the telephone line A with respect to direct current .before leavin'g them,but not Yto telephonie currents, for

the two portions of the line are joined through 15 from either jack, all apparatus associated with the testing line or trunk line B is restored to normal position, and the disconnection of the lugs 5 and 6 from the jacks 3 and 4 restores t e continuity of the line through the contacts of the jacks.

What is' claimed is: f 1. In a telephone system, a telephone line extending between two separated points, ay

trunk. circuit connected with the telephone line at a point intermediate its ends and extending toa switchboard, an extension circuit atthe switchboard, a switching device thereat having two operative positions and when in either connectin the extension circuit with the trunk circuit, switching means responsive-to the connection of the extension circuit with the trunk circuit `when the switching device is in one operative position to open the telephone line and disconnect one end thereof from the trunk circuit, and means including the switching means responsive to the connection of the extension circuit with the trunk circuit when the switching device is in its other operative position to open the telephone line and disconnect the other end thereof. from the trunk circuit. l' 2. In a telephone system, a telephone line extending between two se arated points, a

trunk circuit connected with the telephone line at a point intermediate its ends and extending to and terminating at a switchboard in two jacks, an lextension circuit at the jack to open the telephone line and disconnect the other end thereof from the trunk circuit.

3. In a telephone system, a telephone line extending between two separated points, a trunk circuit connected with the telephone line at a point intermediate its ends and extending to and terminating at a switchboard in two jacks, a plug-ended extension circuit at the switchboard, a switching relay responsive to the connection of the plug of the extension circuit with one jack of the trunk circuit to open the telephone line and disconnect one end thereof from the trunk circuit, a second switching relay responsive to the connection of the plug of the extensioncircuit with the other jack of the trunk circuit to open the telephone line and disconnect the other end thereof from the trunk circuit.

4. In a telephone system, a telephone line extending between two separated points, a trunk circuit connected with the telephone line at a point intermediate its ends and extending to and terminating at a switch' board in'two jacks, a plug-ended extension circuit at the switchboard, an operating circuit established upon the connection of the plug of the extension circuit with either jack of the trunk circuit, arelay in the operating circuit responsive when the plug is connected with one jack to cause the opening of the telephone line and the disconnection of one end thereof from the trunk circuit, and a second relay in the operating circuit responsive to the connection of the plug with the -other jack to open the telephone line and to disconnect the other end thereof from the trunk circuit.

5. In a telephone system, a telephone line extending between two separated points, a trunk circuit connected with a telephone line at a point intermediate its ends and extending to and terminating at a switchboard in two jacks, a plug-ended extension circuit at the switchboard, an operating circuit established upon the connection of the plug with .either jack, two relays in the operating circuit responsive to the connection of the plug with one jack to open the telephone ine and disconnect one end thereof from the trunk circuit, and a resistance included in the operating circuit when the plug is connected. with the other jack, whereby but one relay is responsive to cause the opening of the telephone and the disconnection of the other end thereof from the trunk circuit.

6. a telephone system, a tele hone line extendingbetween two separate points, a trunk circuit connected with the telephone line at a point intermediate its ends and extending to and terminating at a switchboard in two Jacks, a plug-ended extension circuit at the switchboard, and a relay responsive to the connection of the plug-ended extension circuit with the trunk circuit through either of the jacks, and means operating upon the response of the relay to vopen the telephone line and to disconnect one end thereof from the trunk circuit.

7. In a telephone system, a telephone line extending between two separated points, a trunk circuit connected with the telephone vline at a point intermediate its yends and extending to and terminating at a switchboard in two jacks, a plug-ended extension circuit at the switchboard, a relay responsive to the connection of the plug-ended extension circuit with one of the jacks of the trunk circuit, and means operating upon the response of the relay to open the telephone line and to disconnect one end thereof from the trunk circuit.

8. A telephone system comprising a telephone line extended between two separated points, a trunk circuit connected with the telephone line at a point intermediate its ends and extending to and terminating at a switchboard in two jacks, a plug-ended extension circuit at the switchboard, an operating circuit established upon the connection of the plug with either jack, a relay in the operating circuit responsive to the connection of the plug with one jack to cause the opening of the telephone line and the disconnection of one end thereof from the trunk circuit, and a marginal relay responsive to the connection of theplug with the other jack to cause the opening of the telephone line and the disconnection of the other end thereof from the trunk circuit.

9,. In a telephone system, a telephone line, a trunk circuit connected with the line at a point intermediate its ends and extending to a switchboard, operator-controlled switching means at the switchboard, an electromagnetic switching mechanism in the trunk circuit responsive to the actuation Aof the operator-controlled switching means for interrupting the continuity of the telephone line and disconnecting one end thereof from the trunk circuit.

1`0. In a telephone system, a telephone line, a trunk circuit connected with thetelephone line at a point intermediate its ends and extending to a switchboard, an operator-controlled switch at the switchboard, and a relay in the 4trunk circuit responsive to the actuation of the switch to interrupt the continuity of the telephone line and to disconnect one end thereof from the trunk circuit.

In witness whereof, I hereunto subscribe my name this 27th day of March A. D.,

y ERIC R. LUNDIUS. 

